It's also a single broadcast domain.
In other words, if a device like A sends a broadcast, everyone in the network would receive that broadcast
and would need to process the broadcast.
When a device receives a broadcast, it will process it.
In other words, it will receive it on the network interface card and then forward it to upper layers
in the OCI model.
So as an example, the CPU or central processing unit of a PC would be interrupted when a PC receives
the broadcast.
So if device A starts jabbering, in other words, starts sending many, many broadcasts onto the network,
those broadcasts would be received by all the devices in the network, and every device would be interrupted
and would have to process the broadcast so the CPUs of every PC would be interrupted by every broadcast
sent by A and would need to process that broadcast if A was sending a broadcast.
But the traffic was only intended for B, both C and D would still have to receive that broadcast process
it and drop it.
But the problem is they CPUs were interrupted, which may cause the PC to slow down.
Thus, because of the issues with regards to maximum segment length, maximum hosts on a segment and
cable breaks, ten based two was replaced with ten base T ten base RT uses unshielded twisted pair.
It's very unlikely that you're going to encounter ten base two in today's networks.
So ten base T or twisted pair Ethernet refers to the use of cable that contains insulated copper wires
twisted together in pairs with a maximum distance of 100 meters.
The cable is a lot thinner and more flexible than coaxial cable, which was used in both ten base two
and ten base five networks.
In ten t we tend to use unshielded twisted pair cables, shielded twisted peg cables may be used in
noisy environments where there's a shield around each pair of wires, plus an overall shield around
the cables to protect them against excessive electrical magnetic interference.
This may be caused, as an example, where network cables are close to electrical cables, so additional
protection is required.
But most networks tend to use unshielded twisted pair where the cables are not shielded against interference
in the same way.
Once again, ten base t means ten megabits per second base means base band rather than broadband.
T means twisted pair with a maximum segment size of 100 meters.
The connectors used are j 45 connectors as seen here, and you've probably connected an RJ 45 connector
to your PC many times in the past.
Unshielded twisted pair or UTP, is a set of four pairs of wires with each wire in a pair being twisted
around the other to prevent electromagnetic interference.
As an example, notice here we have a twisted pair for pairs.
Make up the UTP used in Ethernet.
Each wire has a color coded plastic insulation and the wires are inside and out a jacket.
In an Ethernet environment, the Y is connected to an RJ 45 connector.
As shown here, the advantage of UTP or Untrusted Pair is it's a less expensive and easier to install
than other cabling implementations such as shielded, twisted pair or coaxial cable.
There are various categories of UTP, which I'll talk about in a moment.
The maximum distance is 100 meters without the use of a signal regeneration device such as a hub or
switch.
So this is the type of cabling you'll probably encounter many, many times in your networking career.
UTP uses RJ 45 connectors.
So let's talk about the PIN positions on an RJ 45 connector.
There are two main implementations which are RT five, six, eight, A and RT five, six, eight B and
there's a slight difference with the pairing of cabling in each implementation.
Tia EIA 568 was developed to define standards for telecommunications cabling systems.
EIA is the Electronic Industry Alliance and is a standards based organization.
Tia EIA 568c attempts to define structured cabling standards.
So the difference between A and B is the pairing of cabling.
Notice in a white green stripe and green solid are connected to pins one and two, whereas in B, white
orange stripe and solid orange are connected to one and two.
So they are subtle differences between the cabling of orange and green in five, six, eight, A and
five, six, eight B.
Now this will make no difference as both configurations wire the pin straight through.
In other words, pin one goes to pin one on both sides of the cable, pin two goes to pin two and so
forth and so on.
So notice on pin one, it's white, green in five, six, eight, a but is white orange in five, six,
eight B The most popular implementation tends to be B, but it will make no difference which one is
used as long as both sides are connected straight through.
Now you could purchase pre-made cables or you may decide to crimp your own cables.
Pre-made cables tend to be more expensive, but have the advantage that they've been tested as well
as the advantage that you don't have to make them yourself.
Crimping cables yourself is cheaper and you can make your cables for the lengths that you require.
When crimping your own cables, you need to separate each individual colored wire in the right order
and then stick each colored wire into the appropriate slot on the RJ 45 connector.
You then use a crimping tool to crimp the wire.
And finally, don't forget to make sure that you test your cable to ensure that you've crimped it correctly.
A straight through cable is a type of twisted pair copper cable, which you're going to find very often
in local area networks or lands in a standard straight through cable.
Each pin of the connector on one end is connected to the corresponding pin on the other connector.
In other words, pin one on the MDI device.
In this case, a PC is connected to PIN one on an MDI device, which in this case is a hub.
PIN two connects to pin, to pin three, to pin three and so forth and so on.
MDI or media independent interface is an Ethernet port connection typically used on network interface
cards or NICS of PCs.
MDI is also used by routers and can be used on uplink ports, on Ethernet switches, on certain older
switches.
You'll see a button normally on the uplink port that allows you to change how that port operates so
you can change the mode from MDI to MDI or back again.
This allows you to connect to one switch to another switch using a straight through cable rather than
using a crossover cable, which I'll mention in a moment.
So in the past, you may have connected your PC to a hub such as these two using a straight through
cable.
Now, straight through cables are used in situations where you connect a PC to a switch or a PC to a
bridge or a PC to a hub.
I'm going to explain how these devices work in a moment and the differences between a hub bridge and
switch.
But from a cabling point of view, you would use a straight through cable from your PC to one of these
devices.
PCs in the past when connecting devices of the same type, such as two PCs or two routers, a crossover
cable would be used.
So in this case, rather than the pins being straight, they crossed.
So in this example, we have two MDI devices.
In other words, two PCs which need to communicate and thus a crossover cable would be required.
This is an example for ten based or 100 based ATX.
In this example, pins four, five, seven and eight are not used.
But notice pin one is crossed with pin three.
PIN two with pin six, pin three with pin one and pin six with pin two.
In other words, the T-x or transmit and RCS or receive are correctly cabled so that TCS X plus is connected
to Orix plus and so forth and so on.
Pins four, five, seven and eight are configured in the straight through format but are unused in this
example.